<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>无标题文档</title>
<script>
//var a=[1,2,3];
//var a=new Array(1,,2,3);
//alert(a.length);
//修改数组的长度
var arr=[1,,2,3,4,5,6];
arr.length=3
alert(arr);
</script>
</head>

<body>
</body>
</html>
